1. Field of the Invention
The present invention relates to an image processing apparatus, and more particularly to an image processing apparatus which is structured to correct, in advance, density unevenness peculiar to a printer unit in a reader unit and a recording medium for use in generating density correction data in the image processing apparatus.
2. Related Background Art
Conventionally, as a printer unit of a copying machine ink jet printers and electrophotographic system printers have been known.
The ink jet system printer performs printing by jetting ink from a nozzle. An output characteristic of the ink jet system printer is featured by density unevenness occurred depending on difference in ink jet quantity. Density unevenness in outputting can be prevented using head shading technology. In this technology, density unevenness is corrected by performing a density data conversion to form multivalue data which corresponds to each nozzle.
The electrophotographic system printer using an LED (light-emitting diode) array head performs printing by lighting LED""s. An output characteristic of the electrophotographic system printer features density unevenness whose occurrences depends on differences in light emission quantity among the LED of the pixels. For this density unevenness, the head shading technology can also be used similar to case of the ink jet system printer. In this technology, density unevenness is corrected by performing density data conversion to form multivalue data which corresponds to each light emission pixel.
In each of the above density unevenness corrections, an image signal output by reading elements in a reader unit, which are arranged in the same direction as that of recording elements in each printer, is sequentially corrected using multivalue data in the order of printing.
A reader unit of a copying machine having a binary outputting printer as a printer unit performs a correction of hue, density or the like on multivalue image data which is read. Thereafter, image data is output to the printer unit by executing area gradation processing depending on binarization processing. Although the correction of hue or density can be performed multivalue data, it is difficult to perform the correction on binary image data on which area gradation processing is executed. That is, it is difficult to perform the correction of hue, density or the like in the printer unit which receives binary data.
Therefore, it is difficult to correct the density unevenness peculiar to the printer unit by processing the binary data in the printer unit. For this reason, it is desired to perform advance correction of density unevenness peculiar to the printer unit on the multivalue image data in the reader unit which is connected to the printer unit and supplies the image data.
In the copying machine, in a case where a printing sheet which has the same direction (orientation) as that of a mounted original is not prepared in a sheet feed cassette, but another printing sheet which has a different direction is prepared, it is desired to improve operability by rotating image data 90xc2x0 and realizing to perform a printing output onto the other printing sheet in accordance with the rotated image data. Further, it is desired to perform the same rotation processing by means of editing processing.
However, according to the conventional density unevenness correction technology, there is found a problem of not enabling the copying machine to perform the rotation processing of the binary image data after the binarization processing of an original image is performed once in the reader unit.
In a case where the density unevenness is corrected corresponding to the main scanning direction (scanning direction) of a reading image using the conventional density unevenness correction technology and the direction of an image to be printed is rotated 90xc2x0 according to the corrected data, the printer unit is to perform a printing of subscanning direction using data, on which the density unevenness correction of the main scanning direction has been performed. That is, a reason for not performing the rotation processing is that the above printing output is regarded as one whose output characteristic peculiar to the printer unit is not corrected and normal unevenness eliminating processing cannot be executed.
An object of the present invention is to solve the above problem.
The present invention provides an image processing apparatus for an image formation apparatus forming images by using a recording element array, which comprises a conversion means for converting image data to compensate recording characteristics of recording elements in the recording element array, a rotation processing means for rotatively processing image data converted by the conversion means, and an output means for outputting image data rotatively processed by the rotation processing means to the image formation apparatus, further comprising:
a control means for controlling the conversion means in accordance with a judgment whether or not the rotation processing means executes rotation processing.
Further, the present invention provides an image processing apparatus for an image formation apparatus forming images by using a recording element array, which comprises a conversion means for converting image data to compensate recording characteristics of recording elements in the recording element array, and a processing means for processing image data converted by the conversion means, further comprising:
a control means for controlling the conversion means in accordance with processed contents of the processing means.
Other objects, structures and effects of the present invention will become apparent from the following detailed description and the attached drawings.